Which of the following common fasteners is referred to as a Turnlock fastener?

The Turnlock fastener is most commonly known as a Dzus fastener. This type of fastener is designed for quick and easy assembly or disassembly of panels and access doors in aircraft and other applications. Dzus fasteners are often used in aviation because they allow components to be securely fastened while enabling quick access for maintenance or inspections.

Dzus fasteners operate with a simple mechanism that involves turning a receptacle to lock or unlock, hence the name "Turnlock." This secure locking feature combined with the ease of use makes them particularly advantageous in aviation settings where modifications and repairs need to be performed frequently and efficiently.

The other fasteners mentioned—hex bolts, rivets, and lock nuts—serve different functions and do not employ the same quick-release mechanism that characterizes Dzus fasteners. They are generally used for more permanent applications and require tools for installation and removal, unlike the quick action of Turnlock fasteners. This distinction emphasizes why Dzus fasteners hold a unique place in the realm of fasteners, especially in aviation.